The application of immune-based therapies to augment the anti-tumor immune response following autologous and allogeneic BMT has dramatically, increased over the past several years. Reconstitution of the immune system following BMT, graft-versus-host disease and post-grafting immunosuppression may modify any immunotherapeutic approach. The need to carefully evaluate, and monitor the immune response in this setting has become increasingly apparent. The principle objective of the Immunological Monitoring Core (IMC) is to provide state of the art immunologic techniques to characterize and quantify the human immune response in support of the five research projects of this BMT program project. While there is great diversity in the therapeutic modalities being evaluated, most areas strongly overlap with regard to analysis and characterization of the immune response. A wide-variety of techniques that enumerate and characterize antigen-specific T cells, assess their functional behavior ex vivo and evaluate the diversity of the T cell response are currently available. Specifically, the goals of the IMC are: . 1. provide technical expertise in monitoring and characterizing the immune response 2. establish standard operating procedures and quality control measures for all immunological assays 3. provide technical support to identify or develop assays specific for all project investigators 4. serve as a repository peripheral blood lymphocytes collected from the patients on the clinical trials